Protection Quarterly Vol.19(1) 2004 33 break off at ground level when pulled (Armstrong personal observation). Control methods for ochna () (Hochst.) In this study we aimed to identify potential control methods for ochna by Walp. in south-east Queensland screening a broad range of chemical and mechanical control options. Rebecca Breaden and Trevor Armstrong, Department of Natural Resources and Mines, Alan Fletcher Research Station, PO Box 36, Sherwood, Queensland Materials and methods 4075, Australia. [email protected] We conducted a screening trial at Chelmer on the banks of the Brisbane River (152°58'8"E, 27°30'43"S) in Queensland, commencing in June 2001. The site was a Summary plantation of native hoop pine (Araucaria We investigated potential chemical and In Australia ochna is grown for its bidwillii Hook.) and bunya pine (A. cun- mechanical methods for controlling the colourful flowers and berries (Csurhes ninghamii Aiton ex D.Don.) Other intro- environmental weed, Ochna serrulata and Edwards 1998) and in Brisbane it is duced present included balloon (Hochst.) Walp., using an unreplicated commonly used in hedges (Hajkowicz vine (Cardiospermum grandiflorum Sw.), screening trial in Brisbane, Queensland. 2002, Breaden personal observation). climbing asparagus (Asparagus africanus The 18 treatments tested included: foliar However, it has escaped from gardens Lam.), Chinese celtis (Celtis sinensis Pers.), spray, cut stump, basal bark and splatter and is now a serious woody weed in the mock orange (Murraya paniculata (L.) gun applications of glyphosate (Glypho- Brisbane area. This has been attributed to Jack.), glycine (Neonotonia wightii (Graham sate® 360), fluroxypyr (Starane® 200), met- prolific fruit production, avian dispersers ex Wight & Arn.) J.A.Lackey), green panic sulfuron-methyl (Brush-Off®), triclopyr (Morton 1998) and dense seedling recruit- (Panicum maximum Jacq.) and Brazilian (Garlon® 600) and dicamba (Kamba® ment (Hajkowicz 2002). Ochna can form cherry (Eugenia uniflora L.). This site had a 500), as well as hand pulling seedlings new from root cuttings (Mbambez- rich alluvial soil, high in organic matter. and digging out adult crowns. eli and Notten 2002), and when the plant The trial was set out in randomly se- The most effective herbicide tested is damaged, vigorous regrowth occurs lected plots. Each plot was 4 m × 10 m (40 was fluroxypyr. All treatments contain- (Muyt 2001). Understorey thickets are m2) and contained three labelled ochna ing fluroxypyr were effective in killing formed, shading out native flora (Muyt plants. Eighteen treatments (Table 1) were ochna, between 10 and 18 months after 2001, Breaden personal observation). An visually assessed at monthly intervals for application. The two mechanical treat- impact ranking by Batianoff and Butler 18 months, using a rating scale of phyto- ments (removal of seedlings and adult (2003) places ochna at 16 on a list of 66 toxicity (5 = plant healthy, 4 = defoliated, 3 crowns) were also very effective. How- priority invasive weeds in south-east = stems green, 2 = stems brown to ground ever these were time consuming and Queensland. level, 1 = dead). Ochna seedling abun- would only be appropriate for scattered Birds are thought to be the primary dance within the plot was also recorded plants or light infestations. dispersers of ochna seed, along with wa- qualitatively (many, few or none) by ter and rubbish dumping (Batianoff and visual inspection in order to identify any Introduction Butler 2003, Lismore City Council 2002). residual effects from the herbicides. Ochna (Ochna serrulata (Hochst.) Walp.) Seeds are contained individually in each Foliar-sprayed bushes were completely () is native to the sub-tropical berry and only germinate when very fresh covered through application with hand- east coast of southern Africa. In its na- (Mbambezeli and Notten 2002). A detailed pumped Swissmex (portable back pack) tive range ochna is widely distributed seed bank survey of heavily infested areas knapsacks of 15 L capacity and Rega 1 mm from sea level to altitudes of 1800 metres, in Toohey Forest (Brisbane) produced no adjustable nozzles. Basal bark spraying of and in many different habitats including ochna seedlings from the soil samples tak- the full circumference of all stems from at forests, rocky hill slopes and grasslands en, suggesting that ochna produces only a least 15 cm to ground level was achieved (Mbambezeli and Notten 2002). The spe- transient seed bank (Morton 1998). with a Swissmex compression sprayer of 8 cies is noted by these authors to grow best Little information exists regarding L capacity with solid stream Rega adjust- in frost-free areas, but can withstand light control of ochna. Much of the information able nozzles. Cut stump applications were frost. is anecdotal and no control trials were done within 15 cm of ground level and The first Queensland Herbarium record identified during our search of the litera- within 15 seconds of cutting with a Phil- of this species was in 1932 (Batianoff and ture. Most of the current information on lips injector ‘splatter gun,’ with a coarse Butler 2003). Ochna is now recorded as controlling ochna mentions glyphosate, nozzle attached by tube to a 2 L back pack invasive in both New South Wales and primarily using the cut stump method. bag. Splatter gun applications used the south-eastern Queensland, and there is Control recommendations vary; for ex- same apparatus set at 5 mL shots per 30 cm potential for the species to be problem- ample, Lismore City Council (2002) rec- of height or width, preferably over reach- atic in other regions of Australia that do ommends cutting, scraping and painting able growing points. Weather conditions not experience heavy frosts. In south- the stump with a 1:1.5 ratio of glyphosate were slightly overcast, but no rain was east Queensland, ochna has invaded to water, while other workers suggest present before, during or after treatment disturbed riparian habitats (Department using neat (undiluted) glyphosate (see application. No wind was present. of Natural Resources and Mines 2002) Hajkowicz 2002). However most glypho- and damp bushland sites such as drain- sate treated ochna re-sprouts later, even Results and discussion age lines, creek beds and eucalypt forest when cut stumps are swabbed close to the The most effective herbicide trialed was edges (Morton 1998). Ochna also grows in ground and within 15 seconds (Armstrong fluroxypyr (Starane® 200) (Table 1). All dry locations (Muyt 2001) and has natural- personal observation). The literature also applications of fluroxypyr (splatter gun, ized in dry sclerophyll forests and ripar- emphasizes complete removal of the root foliar spray, cut stump and basal bark) ian vegetation throughout most of coastal system to prevent coppicing (Buchanan reduced plant vigour until death, which south-east Queensland. These populations 1989). However, the long, tough and occurred 10–18 months after treatment. are believed to be well beyond eradication angled taproot makes this very difficult, Basal bark and cut stump applications (Csurhes and Edwards 1998). even for ochna seedlings, which often of triclopyr ester (Garlon® 600) were also 34 Plant Protection Quarterly Vol.19(1) 2004 Table 1. Effects of herbicide treatments applied to ochna (Ochna serrulata) in south-east Queensland. Trade name Active ingredient Application Treatment Mean final Months to Change in of herbicide product (g L-1 product) rate rating plant death seedling (g a.i. L-1 water) density over time B Starane® 200 fluroxypyr ester (200) 10 Cut stump 1 10 -ve Starane 200 fluroxypyr ester (200) 7 A Basal bark 1 12 0 Starane 200 fluroxypyr ester (200) 10 Splatter gun 1 18 0 Starane 200 fluroxypyr ester (200) 2 Foliar spray 1 18 -ve Garlon® 600 triclopyr ester (600) 19.8 Cut stump 1 12 -ve Garlon 600 triclopyr ester (600) 10.5 A Basal bark 1 12 -ve Garlon 600 triclopyr ester (600) 2.04 Foliar spray 3.33 # -ve Glyphosate® 360 glyphosate (360) 18 Splatter gun 1 12 -ve Glyphosate 360 glyphosate (360) 3.6 Foliar spray 1 12 -ve Glyphosate 360 glyphosate (360) 180 Cut stump 3 # -ve Diesel diesel Neat A Basal bark 2.33 # -ve Brush-Off® + BS 1000 metsulfuron-methyl (600) 0.6 + Splatter gun 2.67 # -ve + non-ionic surfactant 1 mL (1000) Brush-Off + BS 1000 metsulfuron-methyl (600) 0.06 + Foliar spray 3 # 0 + non-ionic surfactant 1 mL (1000) Kamba® 500 dicamba (500) 20 Cut stump 4 # 0 Kamba 500 dicamba (500) 2 Foliar spray 5 # -ve – – – Control 5 # -ve – – – Dig out adult 1 1 0 crowns – – – Hand pull 1 1 0 seedlings A = Diesel as the carrier, # = Death did not occur, B -ve = decrease in seedling density. effective, killing all plants within 12 Hand pulling seedlings and digging Conclusion months. Foliar applications of triclopyr out adult crowns was very effective in con- Fluroxypyr was found to be the most ef- ester were not successful in controlling trolling ochna. Both treatments resulted in fective product trialed on ochna. As all ap- ochna (Table 1). plant death and no regrowth was record- plication methods using fluroxypyr were Glyphosate (Glyphosate® 360) results ed. Mechanical removal occurred when successful, there appears to be the flexibil- were variable. Cut stump applications of the soil was relatively moist, which helped ity to match the most relevant technique glyphosate resulted in regrowth, but the physical removal of ochna roots. However, with the type of infestation (i.e. heavy, splatter gun and foliar spray treatments given the time associated with these treat- dense or scattered and large individuals killed plants (Table 1). Dicamba (Kamba® ments, we conclude that they would only vs. small seedlings). For example, basal 500) and metsulfuron-methyl (Brush-Off®) be time-effective if isolated plants or small bark spraying would suit adult (>2 m tall) were the least effective herbicides trialed. infestations were present. In heavy weed ochna plants, dense infestations would be It is worth noting that many of the infestations, soil disturbance may also suitable for foliar applications, and isolat- herbicide treatments resulted in plants encourage germination of other weed ed ochna plants (<1 m tall) could be splat- appearing dead above-ground shortly af- seeds within the seed bank. Visual assess- ter-gunned. Future work will focus on ter treatment, but resprouting 3–5 months ment of ochna seedling abundance during further testing the effectiveness of flurox- later. These predominantly included the this trial did not indicate that this method ypyr in a replicated trial, to determine the cut stump treatments, fluroxypyr foliar promoted seedling regeneration of this application rates, timing and methods that spray and glyphosate splatter gun and species in a shaded situation. are most effective against ochna. foliar treatments. Seedling numbers stayed constant or Interpretation of our results must take reduced over time in all plots including Acknowledgements into account the drought conditions expe- the control (Table 1). Treatments that were We thank the Foote family who allowed rienced during 2001. Such conditions may very spatially restricted in their applica- us to undertake this trial on their property. have increased plant mortality, particular- tion (i.e. cut stump, basal bark) showed a We also acknowledge the time and effort ly during the later part of the trial when reduction in seedling density, which leads of Fe Ambatali and Robert Galagher dur- treated plants were showing full effects of us to conclude that environmental factors ing the early stages of this trial. Comments the herbicide. Future trials should test the (e.g. drought) or other external influences from Dane Panetta, Gabrielle Vivian-Smith more successful treatments (fluroxypyr were involved. Further research into and two anonymous reviewers improved and triclopyr ester) over several different factors affecting seedling recruitment is earlier drafts of this manuscript. seasons. required. Plant Protection Quarterly Vol.19(1) 2004 35 References Batianoff, G.N. and Butler, D.W. (2003). Impact assessment and analysis of sixty-six priority invasive weeds in south-east Queensland. Plant Protection Quarterly 18 (1) 11-7. Buchanan, R.A. (1989). Bush regenera- tion: recovering Australian landscapes. (TAFE, NSW). Csurhes, S. and Edwards, R. (1998). Poten- tial environmental weeds in Australia: candidate species for preventative con- trol. Queensland Department of Natu- ral Resources, Brisbane, p. 119. Department of Natural Resources and Mines (2002). Ochna or Mickey mouse plant (Ochna serrulata). Environmental Weeds Information Series, QNRM 02180, Land Protection. Hajkowicz, A. (2002). Brisbane Rainfor- est Action and Information Network: Mickey mouse plant (Ochna serrulata). http://www.brisrain.webcentral.com. au/newsletters/issue7/ochna.html. 14 February 2003. Lismore City Council (2002). Weeds: Ochna http://www.liscity.nsw.gov.au/ article.asp?ArticleID=141. 14 February 2003. Mbambezeli, G. and Notten, A. (2002). Ochna serrulata (Hochst.) 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